How ideal weight is calculated
All four formulas give a base weight for 152.4 cm (5 feet) and add a fixed amount per extra inch. Devine (1974) adds 2.3 kg per inch, Robinson (1983) 1.9 kg for men and 1.7 for women, Miller (1983) 1.41 and 1.36 kg, Hamwi (1964) 2.7 and 2.2 kg. The differences show most for tall and short people.
The BMI range is calculated differently: the normal-weight limits 18.5 and 24.9 are multiplied by height squared. That gives a range rather than one number, which is a more honest way to present it. The average of the formulas usually lands mid-way in the BMI range.
Why there is no real ideal weight
The Devine formula was developed in 1974 for calculating drug doses, not as a health or appearance goal. Robinson and Miller tried in 1983 to correct it toward insurance company tables. None of the formulas knows whether your weight is muscle or fat, and none accounts for frame size or limb length.
For a lifter, body fat percentage, waist circumference and strength progress say more than any height-based weight. A muscular 180 cm person can weigh 90 kg and be healthier than a 75 kg formula ideal. Use the numbers as a guide, not a goal.
How to use the result
If your weight is clearly above the BMI range and it is not muscle, the calorie deficit calculator gives a realistic timeline. If you are inside the range, forget ideal weight and look at body fat and waist circumference instead.
Set body composition and strength as goals, not a formula number. Weight changes show best as a weekly average, and strength progress tells whether muscle is preserved along the way.
Frequently asked questions
Is there really such a thing as an ideal weight?
Not a single number. The formulas give a height-based estimate that ignores muscle mass, frame size and body fat. A healthy weight is a range, and for a lifter body composition is a better measure than weight.
What are the ideal weight formulas based on?
The Devine formula (1974) was developed for drug dosing, Hamwi (1964) for clinical assessment, and Robinson and Miller (1983) corrected Devine's formula toward insurance company weight tables. None is based on data from lifters or athletes.
What does the BMI range mean?
The normal body mass index range of 18.5-24.9 multiplied by height squared gives the weight range with the lowest health risks at population level. For an individual, BMI cannot tell muscle from fat, so a muscular person can be healthy in the overweight class.
Why do the formulas give me a weight that is too low?
If you train for strength, your muscle mass is higher than the formulas assume. They were built for the average adult, not for lifters. Look at body fat instead: if it is in the fitness category, your weight is fine regardless of what the formula says.
Should I use ideal weight as a goal?
Only as a rough direction. A better goal is body fat or waist circumference combined with strength progress. The calorie deficit calculator gives a timeline if your weight is clearly above the BMI range.